Screening of coils carrying high-frequency current



Maw 19 1927, 1,628,569

a w sv womwmewm SCREENING 0F COILS CARRYING HIGH FREQUENCY CURRENTS Filed July 27, 1.926

MS M in ior mvemar Patented May 10, 1927.

UNITED STATES PATENT OFFICE.

WALTER SCOTT WORTHINGTON. OF LONDt'lN, ENGLAND.

SCREENING F COILS CARRYING HIGH-FREQUENCY CURRENT.

Application filed July 27, 1926, Serial No. 125,280, and in Great Britain March 11, 1926;

This invention relates to an improved screening arrangement of coils carrying high frequency currents such as tuning or reaction coils and high frequency transformers.

The object of the invention is to provide a screening management which will allow the coil or transformer to be readily replaced by another coil or transformer.

The present invention consists in the combination of a copper or other metal casing capable of being completely closed, with a holder adapted to receive a readily interchangeable coil within the said casing, the said holder being of any known type but preferably of the type comprising two or more metal. sockets adapted to engage with a corresponding number of contact pins provided on the removable coil or transformer.

The invention also consists in the combination of a copper or like disc perforated with a number of holes corresponding to the number of metal sockets which are provided in a suitable base of insulating material to which the said disc is attached, with a suitable cylindrical cover of copper or the like which can easily be removed and. replaced after the coil or transformer has been interchanged and which is adapted to make metallic contact with the said disc and form a complete metallic enclosure for the said coil or transformer.

Another feature of the invention consists in the provision of a bayonet connection between the disc and the cover whilst a still further feature consists in the provision of an earth terminal connected to the said disc, whereby the whole of the casing is earthed when the same is placed in position.

One mode of carrying the invention into effect is illustrated, by way of example, in the accompanying drawings, in which Figure 1 is a sectional elevation of the improved screening arrangement and Figure 2 is a plan "iew of the base with the screening cover and plug-in transformer removed.

A circular copper disc a is secured to a base b of insulating material, the said disc being perforated opposite a plurality of metal sockets c 0 a, 0 0 0 provided in the base I), the holes in the copper disc being of slightly larger diameter than the outer diameter of the said sockets in order not to make any contact therewith. A cylindrical cover d of copper or other suitable metal is secured preferably by means of a bayonet oint e to the said copper disc in such a manner as to make complete metal contact therewith all round its circumference also thereby forn'iing a complete metal enclosure for the coil or transformer f which may have been plugged in position. The base b on which the metal sockets are mounted is also provided with a plurality .of terminals /13 9:57 .73, 94 .95: 96 corresponding to the ber of sockets being connected thereto, and intended to be connected to the various cir cuits. An additional terminal 9 provided on the base is connected to earth and to the metal disc (I, the casing when placed in position being thereby earthed, owing to its being in electric contact with the metal disc. It is to be understood that the invention is not limited to any particular arrangement or number of metal sockets and terminals on the base. Thus in the construction illustrated on the drawing which is intended to be used with. a neutrodyne transformer, four of the sockets are, intended for the terminals of the windings, one for the neutrodyne tap ping and one for the earth connection.

The invention is also applicable to relatively movable coils such as used for instance in connect-ion with reaction coils, in which case the controlling knob is arranged to pass through the copper or like cover in such a manner as not to affect the screening effect thereof. It is also to be understood that the cover must not surroundthe coil or coils at a distance too near the actual wire in order not to increase the high frequency resistance of the coils.

The details for carrying the invention into effect may be modified in other respects without in any way departing from the spirit of the invention.

What I claim is:

1. A screen for coils carrying high frequency currents comprising in combination a metal casing having a fixed and. a detachable part and a base of insulating material serving as a coil holder and having a number of contacts capable of engaging with the usual contacts provided on a detachable coil," said base being secured to the fixed part of the metal casing. said fixed metal part having a number of holes corresponding to the number of contacts on the base for the passage of electric conductors to be connected to the said contacts on the base and the said detachable part of the metal casing being such as to allow, when removed, a replacing of the coil on the base serving as coil holder.

2. A screen for coils carrying high-frequency currents, comprising in combination a base of insulating material having a number of metal sockets and serving as a coil holder, a metal disc attached to the said base of insulating: material and having a number of holes corresponding to the number of metal sockets on the base of insulating material, and a cylindrical cover of metal capable of being easily removed and WALTER SCOTT WORTHINGTON. 

